Solid-state local oscillator sources for millimeter and submillimeter waves in Europe

The author gives an overview of European activities in developing solid-state local oscillator sources for high millimeter and submillimeter frequencies. Radio astronomy with ground-based telescopes has conventionally been the driving force in this area. Projects funded by the European Space Agency and national space agencies targeted at spaceborne radio astronomy and remote sensing of the atmosphere have recently given more impetus to this research. The development of fundamental sources and frequency multipliers is discussed in some detail.<>